


My Little Brother

by kpop7729



Category: Mystic Messenger (Video Game)
Genre: Age Regression/De-Aging, Freeform, Gen, Little Space, Little!Ray, Little!Saeran, Non-Sexual Age Play, Suicidal Thoughts
Language: English
Status: Completed
Published: 2020-07-25
Updated: 2020-07-27
Packaged: 2021-03-05 03:20:14
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 2
Words: 3,164
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25497481
Author URL: https://archiveofourown.org/users/kpop7729/pseuds/kpop7729
Summary: Saeran knows Ray's a little but doesn't accept it. More then anything he just doesn't want Saeyoung to find out. Unfortunately for him, it was impossible for him to repress that side forever. Ray makes an appearance much sooner then he hoped for.
Relationships: 707 | Choi Luciel & Choi Saeran
Comments: 6
Kudos: 62





	1. Meeting Ray

**Author's Note:**

> TW: Mention of Suicidal thoughts
> 
> I'm new to writing for mystic messenger and honestly haven't read all the material/don't remember the game too well, so I may have some information wrong. Consider this an AU of sorts if I'm too off lol. Also, I'm not a little so if anything in this fic offends someone please let me know! It's not an ageplay story but an age regression story. I'm just using the tag so more people can find the story.

Saeran was a mess right now. He couldn’t get his thoughts straight, all he knew is that he couldn’t let his brother find out. He couldn’t let Ray take control, then it’d be all over.

When he was in mint eye, Rika used to take care of him when Ray was...like _that_. Inexcusably weak, a wretched being. How on earth could Ray allow himself to behave in such a way? To what extent was he going to show how truly weak he was? Ray was unmistakably weaker then Saeran but he didn’t expect him to be like this. Really, he was worse than dirt. If he wasn’t in the same body as him Saeran wouldn’t hesitate to end his life. Although Saeran has still entertained the thought a few times here and there.

As long as he didn’t let Ray take over, Saeyoung would never find out. Hiding in his closet wasn’t one of his smartest moves, he knew he could do better, but it was starting to become hard to think rationally. 

He just hoped to god that if Saeyoung found him he would leave him alone. He was afraid that if someone opened the door right now Ray would come bursting out. He needed to be alone right now otherwise his weaker half would take control. 

“Saeran?” He could hear his twin knocking on his bedroom door. Hopefully, if Saeran kept quiet he wouldn’t find him. If you thought about it, the situation was kind of funny. Kind of like they were playing a game of hide and seek. Saeran giggled at the thought but quickly clapped a hand over his mouth. Was he already losing to Ray? His thoughts were starting to become more like his.

“Are you ok?” Saeyoung asked. Saeran had already told him he didn’t want to be bothered!

Earlier Saeran was in the living room. He wasn't really watching the tv, more like fidgeting with the remote and occasionally switching the channel, when a kids station came on. Saeran hadn’t meant to, really! He was a big boy, Rika taught him how to be. How to not give in to the constant childish urges he seemed to have for some reason. But the episode really, _really_ , looked interesting. They were looking for lost treasure for crying out loud, Saeran had to see how this ended! Totally engrossed in the show and forgetting to check the time, Saeran hadn’t realized his brother had come back.

Saeyoung didn’t make a noise, finding it totally adorable how his brother was so engrossed in the kid's cartoon on the tv, the younger occasionally gasping in shock and giggling when something funny happened. It was when the characters found the lost treasure, causing Saeran to let out a “Yay!” of excitement and clap along with the characters on screen, that Saeyoung couldn’t help but let out a coo. Even if he hadn't, his brother was bound to notice him eventually. No matter what he knew that Saeran would give him hell for eavesdropping.

“Aw~ my baby brother is so cute!” Saeyoung couldn’t help but squeal. It was a long time since he’d seen his brother so happy.

Saeran stared at him in shock, his face turning crimson in embarrassment. He screamed “Leave me alone! before bolting out of the room.

Saeyoung had given him some time, before deciding he should make sure he was ok.

That was how they got to their current situation. Saeran wasn’t answering him, but he didn’t want to just barge in.

“Saeran, if you don’t answer I’m gonna have to come in and check on you, ok?” He warned him. He’d give him 60 seconds, and if there was no response he was going in.

60 seconds passed quickly and still no response from his twin. Saeyoung would have to go in, he just hoped Saeran was ok. Even if his brother got mad at him for inviting himself in, he'd be alright as long as Saeran was.

Saeyoung opened the door but didn't see Saeran anywhere. "Saeran?" He called again, but still no response. Had his brother really managed to escape without him noticing?

It was then that he’d heard some shuffling in the closet. So that’s where his brother was.

“Oh where could my brother be, is he hiding from me~?” Saeyoung couldn’t help but tease. He heard some giggles behind the door. Why was his brother so cute today?

“Hmm,” Saeyoung pretend to be pondering the situation, tapping his chin thoughtfully even though there was no one there to see it.

“Is he under the bed?” Saeyoung pretended to check. “Nope~” Cue more giggling. Did his brother really find this that funny? Saeyoung was happy to play along if it made his brother happy.

“Under the desk? No~”

“Hmm, where could he be...Oh, I know! Maybe he's in...here!” Saeyoung said, opening the closet.

Saeran burst into a fit of giggles. “Again, again!” He cheered.

“Wanna play again?” Saeran nodded.

“Ok, you go hide and I’ll count to ten.”

Saeyoung covered his eyes and started counting, and heard his brother's footsteps hurrying away.

Why was his brother acting like this? Don't get him wrong, it was cute, Saeyoung just didn’t understand the sudden drastic change in his brother's behavior. Was it a side effect of everything he endured? Side effect or not, Saeyoung would do anything to help his twin. As a bonus, he got to spend time with his brother again.

Saeyoung made a big show of checking every room, even if his brother wasn’t in them. When he walked into the kitchen he immediately spotted Saeran under the table but pretended not to notice him.

After another three minute show of pretending to be looking for Saeran, Saeyoung bent down and finally said, “Found you~”

Saeran clapped and giggled happily. “Hyungie’s stupid.”

Not minding the usual insult, Saeyoung couldn’t help but make a face of confusion. Saeran’s never called him hyung before. They were twins, even though Saeyoung liked to boast about being the older one. 

“Hyungie.” Saeran pouted, his bottom lip quivering a bit.

“No, shh, don’t cry Saeran. Hyung...just has an upset stomach.” Saeyoung made up.

“Oh. I’m not Saeran though.”

“You’re not?” Saeyoung made sure not to let his confusion show this time, but he was really perplexed by this one. It was definitely his brother in front of him, still under the table. If not Saeran then who was he?

“I’m Ray.” Saeran, or ‘Ray’, declared before plopping his thumb in mouth.

“Oh, well it’s nice to meet you Ray.” Saeyoung extended his hand and Ray shook it with his free one.

“Wou too,” Ray mumbled around his thumb. “Saewan don’t like yow but Way want to meet yow. I want a bwother too.”

“I’m your hyung too. Ray’s also my baby brother.” Saeyoung told him, causing Ray to giggle.

“Weally?”

“Of course!” Because his brother with what could possibly be Dissociative Identity Disorder was still his brother, at least that was one explanation for what was going on. Luckily for Saeyoung, his alter was super cute.

“Weally weally?!” Ray asked. He bounced excitedly under the table, causing him to hit his head. “Owie...” Ray whimpered, rubbing the sore spot. His eyes started tearing up.

“Um...how about we eat some ice cream?” Saeyoung suggested. Anything to keep the younger from crying.

“Ice cream!” Ray shirked in excitement, his mood instantly changing.

“Let’s get you out from the under the table first.” Saeyoung said, helping him out and up.

He sat his brother down, the younger bouncy in his chair cutely while waiting for his ice cream. Saeyoung got him a bowl of strawberry ice cream and got himself a bowl of chocolate brownie ice cream. 

"Yummy!" Ray squealed. He immediately started to devour the ice cream, much like his twin. 

Unfrotently Ray was an extremely messy eater, and when it was apparent there was more ice cream on him then in his stomach, Saeyoung decided to take action. 

"Hey Ray, wait a sec." He took Ray's spoon and started making spaceship noises. "Spaceship 707 taking off, please open wide so it can land!" Saeyoung said, and Ray did as he was told. 

Saeyoung continued to feed him, occasionally taking bites of his own ice cream which was more like soup now. He was happy to sacrifice his precious ice cream if it was for Saeran, or Ray for that matter. They were the same in his mind. 

"Now that the cargo's finished being delivered," Saeyoung said, poking Ray's stomach which made him giggle again. Ray sure was giggly, Saeyoung was glad he got to hear him laugh for once. "Let's get you cleaned up."

Ray whined. "I don't wanna." He pouted, crossing his arms. Saeyoung had to hold back a coo at his adorableness. 

It was Saeyoung's turn to pout. "Oh...well it's ok if you don't want to, but if you don't we can't play, and I _really_ want to play with you." 

Ray's expression turned from sadness to surprise. "No one's ever wanted to play with me before...I'll go clean up right now!" He said, rushing to the bathroom.

Saeyoung chuckled and followed after him. He might need help cleaning himself up, seeing as he could hardly feed himself right now.

Saeyoung was surprised to see that instead of trying to clean himself, Ray was just staring at himself blankly in the mirror. Was this still Ray, or was it Saeran now? Saeyoung wasn't sure how to go about this.

Deciding not to change his behavior just yet, Saeyoung got a washcloth and started wiping the sticky ice cream off of his brother's face. "Let me help you get cleaned up~" Sometimes when people had DID they didn't share the same memories. Saeran might've not remembered anything that happened if this was really him right now. He wanted Saeran to know he still loved him no matter what, in case he hadn't made it clear enough by now.

"You should probably change clothes too, I'll go get you some," Saeyoung told him.

"I can do it myself." His brother, definitely Saeran now, snapped at him. 

Saeran immediately went to his room and didn't come out for the whole night. Saeyoung decided not to press the issue this time. 

The next day, Saeran came, surprisingly to look for Saeyoung out in the living room. "You saw nothing yesterday, understand?" He threatened.

"But you were so cute-"

"Shut up! I'm serious! You didn't see that weak idiot that needed to be babied. You didn't, you didn't, _you didn't_!" Saeran screamed.

"I'm serious too, I missed taking care of you-"

"I don't need to be taken care of!"

"Not always, but we all need to be taken care of sometimes...even if I don't realize that myself most of the time."

Saeran scoffed. "I haven't seen you let someone take care of you." 

"I'm working on it. MC's actually helped me a lot. My daily chip intake has been cut down considerably actually."

"...What's your definition of cutting down?"

"I'm making progress! I used to eat _way_ more than this."

"How are you even still alive?"

"Of course, it is by the power of magic and PhD pepper, the best medicine there is!" Saeyoung declared dramatically.

Saeran pitched the bridge of his nose. "Can you be serious for once?" 

"Sorry, sorry. Seriously, I'd be happy to take care of Ray whenever he comes around." 

"Ray doesn't always need to be looked after."

"Is he a little older sometimes?"

"Usually he's the same age as me, sometimes he lets himself slip...into a younger headspace." Saeran mumbled at the end but Saeyoung still caught it. He was starting to put more pieces together but didn't want to push Saeran until he was ready to talk about it. 

"Well whenever he comes around, I'd like to talk to him, or take care of him, whatever he needs. That goes for you, too."

Saeran snorted. "Figures you'd prefer Ray. He's like the weak brother you once knew."

Saeyoung shook his head. "I don't have a preference. I love you both. And I don't think he's weak. You both endured everything together, didn't you? Do you know how strong you have to be to still be standing here after all that?" 

Saeran didn't know what to make of that. Maybe Saeran had a slight point, but him being even slightly convinced surely wouldn't last long.

"...Maybe I'll come to you."

"Roger! Agent 707 is here at your beck and call whenever you need it!" Saeyoung said dramatically saluting. Saeran rolled his eyes. If he put it like that, maybe Saeran was using him. Maybe he should feel guilty but he sort of liked that thought. Surely he would eventually get tired of taking care of a child, but would properly put up with it to not feel guilty after all he'd done to Saeran, leaving him all alone. At the very least, Saeran could use him.

"Whatever," Saeran told him, before returning to his room.

This could be a fun game, he'd wait until Saeyoung was tired and then spring child Ray on him. Hopefully the weak idiot would corporate with him. 


	2. Saeran is also?

Saeran wasn't sure if Saeyoung had been up for 48 straight hours or what. Maybe he was getting a small amount of sleep, but Saeran could care less. There's no way Ray's presence wouldn't bother his twin right now. He just had to get the former to cooperate with him. Luckily Ray should come out, he was longing to be taken care of. Saeran had made sure to push Ray away as much as possible and avoid any form of affection from Saeyoung. He made sure to even ignore simple questions from the twin. After Saeran pushing them both away as much as possible, Ray was sure to be dying for affection. So much so that hopefully he'd regress. 

Saeran made his way to Saeyoung's computer room. He hoped that weak idiot would come out soon, he was probably trying to avoid it knowing what Saeran was planning. Was Ray afraid Saeyoung wouldn't give him attention? No, his brother would He had to. He had to, and he would suffer. If Saeyoung admitted he couldn't do it anymore and loving him was just an act, at least it would give Saeran conformation. 

Ray wasn't coming out now, but that didn't mean Saeran didn't know how to bring him out. Saeran tried to prepare himself as much as possible for what he was about to do. It was no use, he'd never be prepared enough for this. Taking a deep breath, he knocked on his brother's door. 

"Come in~" His twin sing-songed, knowing it was Saeran at the door.

Saeran peeked his head in. "Hyungie?" Saeran called, trying to make his voice as cute as possible. Ray would defiantly get jealous and come out for attention. 

"Aw Saeran~, or are you Ray? Come to Hyung!" Saeyoung said, patting his lap. Saeran complied, sitting on Saeyoung's lap. 

"How's my cute baby brother?" Saeyoung asked him. 

He felt Ray trying to come out, or at least he thought. It felt sort of different for some reason.

Saeran giggled. Did it sound cute enough? "Good hyungie. Can we play?" Saeran asked, making sure to use his best puppy dog expression. 

"Of course! Just give me ten minutes." Saeyoung told him.

Saeran pouted and felt tears welling in his eyes. Was Ray finally coming then? He hoped so. He was tired of keeping up this act.

"We can have ice cream too if you want!" Saeyoung tried to bribe him with. 

He knew there was a possibility Saeyoung might not have time for him. And he only asked him to wait for ten minutes. But a part of him also hoped that Saeyoung would drop everything for him, would at least try to make it up to him after everything he'd done to him. He'd abandoned him before, and now he was doing it again, wasn't he? For a stupid computer. Was Saeran not interesting enough? Not cute enough? He wasn't fun to play with? Saeran...still wasn't good enough?

He couldn't help tears spilling over at this thought. Of course Saeyoung didn't want him, he was useless. His hyungie didn't even want to play with him, he was only doing it because he felt sorry for him. He had no time for a baby like him. He wanted a big boy brother. 

"Saeran, Ray, I'm sorry! Why don't we play now?" Suddenly he heard Saeyoung's voice near him. Wait, when had Saeran gotten on the floor? Why was he laying on his stomach, his fist hitting the carpet like he was throwing a tantrum? And where was that horrible wailing noise coming from? Was it coming from _him_? Was he Saeran or Ray right now? He hardly knew. He thinks he's Saeran. Vaguely, he knows Saeran and Ray are the same person, both parts of himself, but he didn't want to think about that right now. 

"Hyungie don't leave please!" He latched onto the older, making sure to hug him tightly so he couldn't leave no matter how much he wanted to. 

"Hyung is here. Hyung's not leaving, not ever again," Saeyoung assured, him holding him back just as tightly.

"Do you really mean it?" Saeran couldn't help but ask. There was no way he believed his Hyung. He already left him once, he could do it again for sure!

"Of course! I love you so much, no one could separate us this time no matter how hard they tried! Agent 707 will be sure to fight them off!" 

"You can't leave me! You have to stay by my side forever!" Saeran yelled. 

"I promise Saeran. I'll never leave you again."

Satisfied, Saeran loosened his grip, if only a little bit. 

"Play with me," He demanded, glaring at the older. Saeyoung told him agent 707 was at his beck and call. He was preparing to take full advantage. 

"Hyung'll play anything you want."

"Carry me." Saeran deadpanned.

"Huh?"

"I said carry me!" 

"Your wish is my command," Saeyoung said, letting go of Saeran before bowing. 

Saeyoung lifted Saeran into a piggyback ride, smiling at the younger's giggles. "Go faster!" Saeran barked. Yup, this was defiantly Saeran. 

Saeyoung did his best. If he wasn't tired before he was definitely tired now. But he wouldn't make Saeran cry again. He'd do whatever it takes not to make him cry again, or at least he'd try to keep his tears at bay as much as possible. After all, kids were bound to cry every once and while.

"Put me down," Saeran told him. Saeyoung complied.

"You're too slow," Saeran complained before sticking his tongue out at him. "Go get my ice cream." He ordered, walking into the kitchen. 

Whether he was Saeran or Ray, it didn't matter. His baby brother was still adorable. 


End file.
